Hydrocarbons, such as oil and gas, are commonly obtained from subterranean formations. The development of subterranean operations and the processes involved in removing hydrocarbons from a subterranean formation are complex. Typically, subterranean operations involve a number of different steps such as, for example, drilling the wellbore at a desired well site, treating the wellbore to optimize production of hydrocarbons, and performing the necessary steps to produce and process the hydrocarbons from the subterranean formation.
In order to understand the formation testing process, it is important to understand how hydrocarbons are stored in subterranean formations. Typically, hydrocarbons are stored in small holes, or pores, within the subterranean formation. The ability of a formation to allow hydrocarbons to flow between pores and consequently, into a wellbore, is referred to as permeability. Additionally, hydrocarbons contained within a formation are typically stored under pressure. It is therefore beneficial to determine the magnitude of that pressure in order to safely and efficiently produce from the well.
Drilling operations play an important role when developing oil, gas or water wells or when mining for minerals and the like. A drilling fluid (“mud”) is typically injected into a wellbore when performing drilling operations. The mud may be water, a water-based mud or an oil-based mud. During the drilling operations, a drill bit passes through various layers of earth strata as it descends to a desired depth. Drilling fluids are commonly employed during the drilling operations and perform several important functions including, but not limited to, removing the cuttings from the well to the surface, controlling formation pressures, sealing permeable formations, minimizing formation damage, and cooling and lubricating the drill bit.
One of the methods used during drilling operations is the Reelwell Drilling Method (“RDM”) developed by Reelwell of Stavanger, Norway. In accordance with RDM, as shown in FIG. 1, a dual string drill pipe 102 comprising an inner pipe 104 and an outer pipe 106 is inserted into a wellbore 108 that passes through a formation of interest 110. The drilling fluid may be directed downhole through the annular channel 112 of the drill string and exits the dual string drill pipe 102 through a Bottom Hole Assembly (“BHA”) 114. Return ports 116 are provided above the standard BHA 114. The BHA 114 may include a number of components such as, for example, the drill bit, the bit sub, a mud motor, stabilizers, drill collar, heavy weight drillpipe, jarring devices and/or cross overs for various threadforms. The returning drilling fluid (which contains the cuttings) is directed into the return ports 116 and flows through the inner pipe 104 back to the surface. The return ports 116 of the RDM may be used to clean the wellbore when performing drilling operations by facilitating removal of drill cuttings through the inner pipe 104. Additionally, a piston 118 may be coupled to the outer pipe 106 to provide weight on the drill bit. The piston 118 may push the dual string drill pipe 102 forward by putting hydraulic pressure on the drill bit in the BHA 114. Additionally, the piston 118 may act as a barrier preventing the loss of annular well fluids.
However, the typical RDM methods has a number of drawbacks. First, only a portion of the dual string drill pipe 102 may be utilized for directing the drilling fluid downhole. Specifically, the drilling fluid may be directed downhole through the annular channel 112 between the inner pipe 104 and the outer pipe 106 because the inner pipe is utilized for returning the drilling fluid to the surface. This limits the rate at which drilling fluid can be delivered to the drilling location. The limitation on the rate of delivery of drilling fluids may adversely impact the drilling operations. Moreover, hydraulic motors relying on hydraulic pressure are often used when performing drilling operations. Therefore, the limited rate of delivery of drilling fluids results in less hydraulic pressure being available downhole for a hydraulic motor. Moreover, the piston 118 that places weight on the drill bit 114 is fixed so when the section of liner or casing it is in is reached, the drilling has to stop and the piston pulled to reposition it. Further, typically, the piston 118 can not be easily removed or collapsed to facilitate extra flow area for cementing operations. Finally, in order to perform drilling operations using the RDM, sections of the inner pipe 104 and the outer pipe 106 need to be laid out on the surface and cut in predetermined lengths to form matching pairs of inner and outer pipes that can form segments of the drillstring. This process adds to the cost of performing the drilling operations and consumes valuable time.
Moreover, cementing operations are another part of performing subterranean operations. For instance, it may be desirable to isolate section of the wellbore by forming one or more cement plugs therebetween. During typical cementing operations, a cement mix is prepared at the surface and pumped downhole to a desired location. When preparing the cement mix, it is important to carry out accurate calculations to determine the setting time and pump the mix downhole accordingly so that the cement mix cures at the perfect time at the particular location of interest. Specifically, if the cement mix cures too early or too late it may not form the cement plug at its intended location.
While embodiments of this disclosure have been depicted and described and are defined by reference to exemplary embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and are not exhaustive of the scope of the disclosure.